Water-repellent glass fiber fabric



Patented July 29, 1952 WATER-REPELLENT GLASS FIBER v FABRIC Games Slayter, Newark, Ohio, assigncr to Owens- Corning Fiberglas Corporation, a corporation of Delaware No Drawing. Application August 1, 1947,

Serial No. 765,620

14 Claims.

This invention relates to vapor permeable, water-repellent fabrics and. the methods for producing the same.

An object of this invention is to produce a fabric or cloth of glass fibers which militates against permeation by liquids such as water, but may be permeated by vapors under most conditions of humidity and temperature to which it might be exposed. I

Another object is to produce a foraminous glass fiber fabric or cloth made up of relatively coarse and line fibers in which the fine fibers conceal certain of the interstices and aid in militating against the passage of liquid, such as water therethrough. i

A further object is to produce a method of making a glass fiber fabric orcloth'of the above character.

In one aspect of this invention, a fabric of closely arranged coarse and fine glass fibers is produced, the same being rendered water repellent by a coating or substance, which, when insolubilized on the surfaces of the glass fibers, adheres thereto in the presence of water, and being bonded by an adhesive to prevent such fiber tarpaulins and other water-repellent products rfabricated from sheet stock.

Everyone, at some time or other, has experienced the discomfitures resulting from the use of an article of clothing that is impervious to the passage of moisture, and especially when the humidity is relativelyhigh, such for example as a raincoat. This result is not only encountered with fabrics having a continuous film that operates as a moisture barrier, but is also experienced with other textile fabrics of interwoven cotton, wool, or synthetic resinous fibers treated with a water-repellent material. Garments manufactured from the lattergroup of materials .are quite comfortable to wear under normal conditions but they generally become almost unbearable when exposed to weather conditions for which they were actually designed.

There is reason to believe that most of these fabrics are very closely woven for the purpose of reducing the interstices through which water might pass, and under normal humidity conditions sufficient porosity is afforded to enable the fabrics to breathe. However, as the humidity increases, as whenit rain-s, the cotton, wool and synthetic fibers absorb moisture and swell and thereby greatly diminish the perviousness or permeability of the fabric. This undesirable absorption appears to take place even though the fibers are coated with water resistant material, because practically every water-repellent treating material is an organic compound having some degree of moisture transmission.

The resulting swelling of the fibers not only provides a barrier to the free passage of vapors or. gases through the fabric, but due perhaps to the resulting compactness of the fibers and possible readjustment or release of the water-repellent coating, the ability of the fabric to prevent the seepage of water therethrough is greatly diminished. This is readily shown when the underside of an awning or tent is touched by a finger during a prolonged rain storm.

H The penetration of water through such waterrepellent fabric may be further explained by the fact that woolen, cotton or synthetic resinous fibers are noticeably softened by the absorbed moisture. For this reason, they appear to be more readily fiexed, stretched and compressed causing changes in fiber dimensions during normal wear, enabling a type of pumping action to take place and force water through the interstices, as well as, enabling such fiber displacement as will enlarge the interstices in various portions under stress to permit the free passage of water.

I have found that a fabric that constantly sheds water and is able to maintain the desired degree of porosity at high and low humidity conditions, may be manufactured from glass fibers, the surfaces of which have been treated to exhibit hydrophobic characteristics instead of the hydrophilic properties natural to unmodified glass surfaces. The desired conversion may be effected by treating'the glass fibers before or after they are arranged into a fabric with a water-repellent substance, which, when insolubilized on the glass fiber surfaces, preferentially adheres to glass in the presence of water and, as a result, is not displaced thereby.

The fabric is advantageously formed of interwoven strands or yarns of glass fibers of the continuous type, that is, strands or yarns in which the individual fibers are coextensive with the strand or yarn. It may, instead, be formed of staple (discontinuous) fibers, that is, shorter lengths of fibers, which are intermatted and interlaced to form strands for interweaving, or felted and bonded in haphazard or jackstraw arrangement in a relatively fiat layer or mat. The individual fibers in either case generally are in the range of 5 to microns in diameter and provide a flexible, supple fabric. However, these dimensions are not to be taken as limitations because larger and smaller fiber diameters may be employed to advantage.

I have discovered further, that the ultimate water-repellent properties of the fabric are improved by the incorporation of small amounts of very fine glass fibers, especially of the staple type, ranging in diameter from one to three microns or less. Ordinarily, the incorporation of about ten per cent of the fine glass fibers is sufficient advantageously to improve the water shedding characteristics of the fabric. These fine glass fibers may be incorporated as a strand plied with the other strands of the coarser fibers and used as the warp or fill, or both, of the woven fabric, or the fine glass fibers may sepa rately form a yarn to be used as the warp or fill, or both of the fabric. "Fabrics containing the desired amount of fine glass fibers may be produced by intermixing relatively short lengths of the fine fibers with the coarser staple fibers before they are haphazardly arranged in the mat or intermatted or interlaced into yarns containing the two kinds of fibers in relatively uniform distribution.

The noticeable improvements derived from the use of fine glass fibers in combination with the coarse fibers appears to reside in the ability of thefine fibers substantially to eliminate the interstices in the fabric through which Water or other fluid might otherwise pass. This characteristic is believed attributable to the more fuzzy nature of very fine fibers and is especially noticeable in the case of strands of fine fibers of the staple type where there is fuzz or large numbers of free ends projecting from the side walls of the strands. The fine fibers by projecting into the interstices of the fabric, cover and practically eliminate the openings through which water might otherwise pass, and when treated with a water-repellent material, effectively prevent passage of-water.

The individual glass fibers are rendered permanently water repellent by treatment with a material which, when insolubilized on the glass fiber surfaces, preferentially adheres to the glass fiber surfaces in the presence of water and is not replaced thereby and is constituted with hydrophobic groups in position to protect the glass surfaces. Thus, a new fiber surface is presented, which for all practical purposes is hydrophobic in character and repels water or other like substances. It is notnecessary that a high concentration of the treating compound be provided on the glass fiber surfaces, a monomolecular layer being sufiicient. A suitable amount is readily provided by a composition containing atom through carbon and, when polymerized, the

silicon atoms are joined to the other silicon atoms through divalent oxygen or organic radicals. Included also are the compounds in which an organic group is attached to the silicon atom through oxygen.

The general formula RnSiX4-n is representative of the hydrolyzable organi-silicon compounds, where X is a readily hydrolyzable group such as hydrogen, halogeno, amino, alkoxy, aroxy or acyloxy and the like; R is an aliphatic, alicyclic, aromatic, mixed aromatic-aliphatic, or heterocyclic monovalent radical. When aliphatic or mixed aliphatic-aromatic, the aliphatic group may be saturated or unsaturated, branched or straight chained, substituted or unsubstituted. These materials generally are applied from solution in aromatic, petroleum, or coal tar solvents, chlorinated solvents, esters or ketones but may equally be applied from an aqueous emulsion if in the fully polymerized or condensed form.

Example 1.A composition based on an organo-silicon compound may contain:

1-10 per cent octadecyl-trichloro silane 99-90 per cent high-flash naphtha Instead of the high-flash naphtha other aromatic solvents, petroleum distillates, chlorinated hydrocarbon solvents such as perchloroethylene, tetrachloroethylene, ethylene dichloride, ketones and esters or mixtures thereof may equally be used. The octadecyl trichloro silane may be replaced wholly or in part by other hydrolyzable organo-silicon compounds and derivatives thereof, such as diphenyl polysiloxane, dioctadecyl dichloro silane, di-dodecyl triethoxy silicane and the like, or replaced in part by hydrocarbon oils and waxes.

Th fabric or cloth of glass fibers, preferably heat treated to remove the originally applied size, is drawn through a bath of the above composition. The excess may be removed by a roller or wiper blades and the treated fabric baked from 1 to 15 minutes at 200 F. to 350 F. for setting and insolubilizing the or-gano-silicon compound on the glass fibers. During the bake, the volatile acids are removed and the fabric is in better condition for subsequent binder application, as will hereinafter be described.

Example 2.--An aqueous composition based on an organo-silicon compound may contain:

1-10 per cent diphenyl polysiloxane of 200 to 500 centistokes 98-89 per cent water 1.0 per cent octadecyl ammonium chloride emulsifying agent The materials may be formed into an emulsion and sprayed onto the fibers as they are rained down from above onto a moving belt. When insolubilized on the surfaces of the glass fibers, such, for example, as by a subsequent bake of from 1 to 15 minutes at 300 F. to 700 F., the coating adheres strongly to the glass fiber surfaces and is not replaced by water. The resinous compound additionally operates to protect the glass fibers from the effects of abrasion.

Instead of an organo-silicon compound or in combination therewith, the treating composition may comprise a complex compound of the Werner type in which a trivalent nuclear chromium atom is co-ordinated with an acido group having at least 10 carbon atoms. These compounds are initially water soluble but become insoluble when dried on the surface of the glass fiber, the long chain alkyl group imparting hydrophobic characteristics to the glass fiber surfaces. In practice, application is made from an aqueous solution having a small amount of an alcohol, such as isopropyl alcohol," for stabilization purposes.

Example 3.-A treating composition formulated with a Werner oomplex'compound may contain:

2 parts of the reaction product; of oleic acid and chromyl chloride prepared in accordance with one of the processes described in the Iler Patent No. 2,2'73,040 issued on February 1'7, 1942 8 parts isopropyl alcohol 90 parts water The solution is wiped onto the glass filaments as they are drawn from the molten glass and collected into the form of a strand. The residue of green coloration, after the volatile have been removed, as by an air dry or short bake, operates as a lubricant for protecting the fibers one from another and at the same time imparts hydrophobic characteristics to the glass fiber surfaces. The adhesion tension of the complex for glass surpasses that of moisture and the complex stronglyadheres to the glass surfaces even in the presence of water.

' Alternatively, the desired water repellent characteristics may be derived from a cationicactive substance. By a cationic-active substance, as that expression is used, there is meant the onium salts of a basic compound of nitrogen, phosphorus or sulfur capable of dissociation in water into an anion, and a positively charged cationic group, which contains the water repelling organic group having at least 10 1 has a previously applied size harmful to the carbon atoms, and is insolubilized on the surface of the glass by heat or an air dry. A suitable cationic-active substance in the form of an onium salt may be illustrated by the following formula: v

where Y is an atom of nitrogen, phosphorus or sulfur; R is an organic radical having at least 10 carbon atoms; R1 and R2 are hydrogen or low molecular weight organic radicals; Xis a highly ionizable anion of the type chloride, bromide, iodide, nitrate, acetate, form-ate .propionate or an oxylate of the type oxyacetate and the like; and A is either hydrogen or a monovalent organic radical. I

In specific application, the onium salt may be-dissol-ved-in'an aqueous medium or elsethe base amine, that is-without A and 'X attached to the Y group, may be dissolved in an aqueous medium containing an inorganic or organic acid of the type of AX. In either case, the cationicactive onium salt ionizes to an anion and the cationic-active compound containing the long chain radicals, which may be insolubilized on tially difiicult to remove except by heattreatment.

Examples of cationic-active compounds suit- 1 Application of the water-repellent may be made in any suitable manner before or after the fibers are arranged in their respective positions in the fabric. For example, the fibers may be treated by running the filament, strand,

the glass fiber surface from which it is substanproperties desired, it may be first removed by a suitable heat treatment or wash. Alternatively, the treating composition may be sprayed, flow coated or brushed onto the fibers. In application of the organo-silicon compounds of the silane type, suitable deposition may be made by condensing the vapors thereof on the fiber surfaces.

When the water-repellent is also capable of functioning as a lubricant or a protective coating, a number of advantages are derived from the application to the fibers before they are formed into the respective strands or fabric, such for example, as spraying the composition on the shorter length fibers as they are rained down from above and gathered .into a mat during their manufacture, or by wiping the compositionon the continuous glass filaments as they are attenuated from the molten glass and gathered into strands. In this capacity, the water'- repellent operates additionally to lubricate the fibers and protect them from abrasion one with another or adjacent processing devices.

The fabric is preferably treated to set the fibers or the weave of the strands. This is to prevent subsequent slippage or relative movement, which might enlarge the interstices between the fibers or cause water to penetrate through the fabric by a type of pumping action.

Weave-setting may be effected by a wide variety of resinous materials, which are taken-to include the resin forming organo-silicon compounds, the thermosetting resinous reaction products generally grouped under the names phenol-formaldehyde, urea-formaldehyde, melamine-formaldehyde, the polyesters, polyamides, and the allyl esters and their copolymers with unsaturated monomers of the styrene or acrylate type. Also included .as binder. are the thermoplastic resins, such as the vinyl acetates, vinyl chloride-vinyl acetate copolymers, vinyl acetals, vinylidine chloride vinyl chloride copolymers, polystyrene, polyalkylacrylates, cellulose ether and the various natural resinsof the type shellac, cumarone-indene,'rosin, and mixtures of the various thermoplastic resinous materials with plasticizers. I i

Weave-setting and water repellence maybe achieved by treating with a single material, such as a resin forming organo-silicon compound reacted to an intermediate stage of its polymeric growth. These generally are taken to include the organo-silicon polymerizable products of,a silane having an R to Si ratio of less than 2 to 1, such as dimethyl polysiloxane, the copolymer of phenyl' methyl, phenyl and methyl silicane, the copolymer of dimethyl, phenyl and methyl silicane and the like.

More often the water-repellent and the weavesetting material are applied from a single composition. When one of the constituents of the composition comprises an organo-silicon component, the other generally must be capable of withstanding the elevated temperaturesrequired tofix the former onto the glass fiber surfaces;v that is a temperature in the range of 300 F. to 700 F, "For example, when the water-repellent is an organo-silicon, then another organo-silicon, phenol formaldehyde, melamine formaldehyde 7 or polyester resinous materials may be applied therewith.

Example 4. A single'treating composition may contain:

0.5 per cent trimeric phenylethyl silicane 2.0 per cent copolymer phenyl methyl, phenyl, methylsilicane 97.5 per cent fhighfiash naphtha Instead of the trimeric phenylethyl silicaneany other of the silanes previously described may be used although preference is given to the low molecular weight polymerization products. The phenylmethyl, phenyl, methyl silicane copolymer may equally comprise other resinous organo-silicon polymers such, for example, as dimethyl, phenyl, methyl siloxanes, phenyl ethyl siloxanes, methyl silicones and the like. The fibers of the fabric are dipped into the solution and the excess composition removed by wiping or squeeze rolls. The fabric is then baked for about 3 to 30 minutes at 350 F. to 600 F. During the bake the resinous material is insolubilized on the glass fiber surfaces and the fibers are joined one to another at their intersections.

Greater latitude in combining the two steps of effecting water repellence and weave-setting is enabled when the water-repellent is one of the Werner complexes or cationic active substances. The latter is particularly suitable, as it operates in aqueous medium as an emulsifying agent and stabilizes the resinous composition.

In specific application, weave-setting preferably is effected apart from the treatment of the fibers for water repellence. That is, after the fibers individually are coated with the waterrepellent, whether it be before they are formed into a strand or fabric, while they are thus being formed, after they are in their fabric form,.or after the impurities have first been removed from the fabric by a heat treatment or wash, the resinous binders are applied by a dip, spray, roll coat, brush or other suitable process and heated to drive off the solvents or cure the resin. Ordinarily concentrations of 2 to per cent by weight of resinous material in the applied solution or emulsion is sufficient, especially if the resinous material is of the type which does not readily wet the water-repellent glass surfaces and migrates to the intersection, more effectively to bond the fibers one to another. Porous vapor-permeable and water-repellent fabrics have been made when the applied resinous compositions contained as much as 25 per:cent by weight of solids.

When' the water-repellent is an organo-silicon compound, the halogen containing polymers are often used in the after treatment and for weaves etting. A suitable formulation for fibers rendered water-repellent by a composition of the type set forth in Examples 1 or 2 may contain:

Example 5 g I 10.per cent vinyl chloride vinyl'acetate copolymer 2 per cent tri-cresyl phosphate 2 per cent of a polyester resin.

86 per cent cyclohexanone The formulation may be further modified by the incorporation of small amounts ofanamino complex ofa metal soap, such as is formed by the'reaction of monoethanolamineor n-butyl ethanolamine with aluminum or copper stearate', oils, waxes and "other resinous materials, such for example, asa resin forming 'organo-silicon 8 compound. When desired pigments rangin from 5 to 30 per cent of the total solids may be incorporated.

Application to the water -repellent fibers may be made by the dip or other suitable process and the excess removed by rollers or wiping blades before it is baked at 300 F. to 375 to remove the solvents.

The invention also contemplates the production of fabrics having the appearance and function of leather but which are very porous, permeable to vapors and impermeable to water. These fabrics are more suitable for some purposes than leather, which absorbs moisture unless treated, but when so treated it also becomes impervious to vapors and gases. Leather-like fabrics are made by compacting and felting into sheet form a multiplicity of fine glass fibers, that is fibers ranging from 1 to 5 microns in diameter, but preferably 1 to 3 microns in diameter. Fibers suitable for this purpose are also of relatively short length, ranging from ,1 to inch. These shorter fibers may be produced from fibers of greater length by cutting, chopping or milling in a hammer or cutter type mill.

Either before or after reducing their lengths, the fibers are coated with the desirable waterrepellent and weave-setting materials, such as the organo-silicon compounds, cationic active substances, or the Werner complexes in combination with suitable resinous binder selected from the group previously described. The water-repellent and weave-setting materials may comprise a single organo-silicon resinous material. These are applied in the usual manner, that is, by flow coating, dipping or spraying the dilute composition or compositions, as the case may be, onto the fibers as they are collected and felted into a relatively flat layer. The felting of the fibers is continued until the mat is at a density of about 20 to 40 pounds per cubic foot. The felted mat or sheet is then baked to set the water-repellent, volatilize the diluent, and set the binder.

While the ultimate object is secured with a glass fiber. fabric in which the individual fibers are adhered one toanother at their intersections with a weave-setting or binder material, it will be readily understood that a foraminous fabric or cloth of glass fibers, the individual fibers of which have been treated with a waterrepellent is likewise an article of manufacture having many of the desirable properties. Fabric's made in accordance with this invention are light in weight, porous, permeable to the passage of vapors and gases yet impervious to liquids, such as water.

It is to be further understood that numerous changes/in the details of formulating the materials and composition, their methods of application, and the arrangement and distribution of glass fibers in the fabric may be effected without departing from the spirit of the invention, especially as defined in the following claims.

I'claim:

1. In a fabric having the characteristics of water repellency and vapor permeability, glass fibers of substantially endlesslengths and diameters greater than 5 microns formed into a fabric, a small amount of ultra fine glass fibers of relatively short lengths and having diameters less than 3 microns interspersed with the fabric forming fibers, the latter ultra fine fibers providing'numerous' ends which extend outwardlv substantially to close the interstices of the fabric, and a water-repellent insolubilized on the glass fiber surfaces.

2. In a fabric having the characteristics of water repellency and vapor permeability, glass textile fibers of relatively long length and having diameters greater than microns formed into a fabric, less than percent by weight of relatively short glass fibers of less than 3 microns in diameter interspersed with the glass textile fibers toprovide numerous fuzzy ends which extend outwardly substantially to close the interstices of the fabric, and a water-repellent coating the glass fibers to impart water repellency and vapor permeability tothe fabric.

3. A fabric as claimed in claim 2 in which the interstitial closing glass fibers are less than /8 inch in length.

4. A fabric as claimed in claim 2 in which the water-repellent comprises an organo-silicon compound.

5. A fabric as claimed in claim 2 in which the water-repellent comprises a Werner complex of the type having an acido group of more than 9 carbon atoms coordinated with the nuclear trivalent chromium atom.

6. A fabric as claimed in claim 2 in which the water-repellent comprises a cationic-active onium group having an organic group containing more than 9 carbon atoms.

7. A fabric as claimed in claim 2 in which the water-repellent comprises an organo-silicon compound deposited from a composition containing less than 2 percent by weight, and a resinous adhesive deposited from a composition containing 1 to percent of a resinous material.

8. In the method of producing a vapor-permeable, water-repellent fabric comprising arranging a multiplicity of glass textile fibers of substantially endless lengths and diameters greater than 5 microns in combination with a small amount of ultra fine glass fibers of relatively short lengths and less than 3 microns in diameter dispersed with the textile fibers into fabric form whereby the ultra fine glass fibers provide a multiplicity of fuzzy ends which extend from the fabric and substantially close the interstices thereof, and treating the fibers to insolubilize a water-repellent thereon.

9. The method of producing a vapor-permeable, water-repellent fabric as claimed in claim 8 in which the textile fibers and the ultra fine glass fibers are formed into yarns and treated with the water-repellent compound prior to arrangement in fabric form.

10. The method as claimed in claim 8 which includes the additional step of coating the fabric of glass fibers treated with a water-repellent with a composition containing 1-20 percent by weight of a resinous adhesive, and removing the diluent to soldify the resinous material on the glass fiber surfaces.

11. The method as claimed in claim 8 in which the water-repellent applied to the glass fiber surfaces comprises an organo-silane in concentrations less than 2 percent by weight in the treating composition and which includes the additional step of insolubilizing the silane on the glass fiber surfaces by heat treatment to remove the diluent and set the organo-silicon compound on the glass fiber surfaces.

12. The method as claimed in claim 11 in which the heat treatment for insolubilizing the organo-silane on the glass fiber surfaces comprises heating the treated glass fibers while in fabric form to a temperature in the range of 300-700 F.

13. In the method of producing a vapor-permeable, water-repellent fabric comprising arranging a multiplicity of glass textile fibers of substantially endless lengths and diameters greater than 5 microns in combination with a small amount of ultra fine glass fibers of a length less than 4; inch and less than 3 microns in diameter dispersed with the textile fibers into fabric form whereby the ultra fine glass fibers provide a multiplicity of fuzzy ends which extend from the fabric and substantially close the interstices thereof, and treating the fibers to insolubilize a water-repellent thereon.

14. The method of producing a vapor-permeable, water-repellent fabric comprising forming strands of glass textile fibers of substantially endless lengths and diameters greater than 5 microns and less than 10 percent by weight of ultra fine glass fibers having lengths ranging from 4 to A; inch and less than 3 microns in diameter, treating the glass fibers with an organo-silicon compound to impart Water repellency and then forming the strands into a textile fabric.

GAMES SLAYTER.

REFERENCES CITED The following references are of record in the file of this patent:

OTHER REFERENCES Modern Plastics, page 112, December 1946. (Copy in Div. 67, Class 154--Silicone.) 

1. IN A FABRIC HAVING THE CHARACTERISTICS OF WATER REPELLENCY AND VAPOR PERMEABILITY, GLASS FIBERS OF SUBSTANTIALLY ENDLESS LENGTHS AND DIAMETERS GREATER THAN 5 MICRONS FORMED INTO A FABRIC, A SMALL AMOUNT OF ULTRA FINE GLASS FIBERS OF RELATIVELY SHORT LENGTHS AND HAVING DIAMETERS LESS THAN 3 MICRONS INTERSPERSED WITH THE FABRIC FORMING FIBERS, THE LATTER ULTRA FINE FIBERS PROVIDING NUMEROUS ENDS WHICH EXTEND OUTWARDLY SUBSTANTIALLY TO CLOSE THE INTERSTICES OF THE FABRIC, AND A WATER-REPELLENT INSOLUBILIZED ON THE GLASS FIBER SURFACES. 